<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>03关键帧</title>
    <style>
        .outer{
            height: 500px;
            border-bottom: 10px solid black;
            margin: 50px auto;
            overflow: hidden;
        }
        .outer div{
            float: left;
            width: 100px;
            height: 100px;border-radius: 50%;
            background-color: #bfa;
            animation: ball 2s 20 alternate-reverse forwards linear;
            animation-delay: ;
        }
        div .box1{
            background-color: orange;
            animation-delay:.1s;
           
        }
        div .box2{
            background-color:yellow;
            animation-delay:.2s;
           
        }

        div .box3{
            background-color: yellowgreen;
            animation-delay:.3s;
           
        }

        div .box4{
            background-color: green;
            animation-delay:.4s;
           
        }

        div .box5{
            background-color: blue;
            animation-delay:.5s;
           
        }

        div .box6{
            background-color: purple;
            animation-delay:.6s;
           
        }

        div .box7{
            background-color: rebeccapurple;
            animation-delay:.7s;
           
        }

        div .box8{
            background-color: red;
            animation-delay:.8s;
           
        }

        div .box9{
            background-color: #bfa;
            animation-delay:.9s;
           
        }


        @keyframes ball {
            from{
                margin-top: 0;
            }
            20%,60%{
                margin-top: 400px;
            }
            40%{
                margin-top: 125px;
            }
            80%{
                margin-top: 250px;
            }
            to{
                margin-top: 400px;
            }
            
        }
    </style>
</head>
<body>
    <div class="outer">
        <div class="box1"></div>
        <div class="box2"></div>
        <div class="box3"></div>
        <div class="box4"></div>
        <div class="box5"></div>
        <div class="box6"></div>
        <div class="box7"></div>
        <div class="box8"></div>
        <div class="box9"></div>


    </div>
    
    
</body>
</html>